understanding and compensating emittance diluting effects in highly optimized ultrafast electron diffraction beamlines

• DOI: 10.18429/jacow-ipac2018-thpaf024
• Publication Date: 2018-01-01
• Authors: Jared Maxson; Christopher M. Pi...; Stanislav Baturin; Yongsun Kim; Colwyn Gulliford; Ivan Bazarov; Matthew Gordon
• Keywords: 05 Beam Dynamics and EM Fields; D09 Emittance Manipulation, Bunch Compression and Cooling; 7. Clean energy; Accelerator Physics

The application of Multiobjective Genetic Algorithm optimization (MOGA) to photoemission based ultrafast electron diffraction (UED) beamlines featuring extremely low cathode mean transverse energies has lead to designs with emittances as low as 1 nm for sub-picosecond bunches with 10⁵ electrons*. Analysis of these results shows significant emittance growth during transport: with emittance dilution as high as a factor of 200-4000% for various designs and optics settings. In this study we quantify and model the individual sources of emittance growth (slice mismatches and space charge), and explore the use of the core emittance as a strong invariant.<br/>Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada<br/>